How Can I Tell if Someone Is Lying

Decades of private and public research all lead to the same conclusion: Spotting a liar is nearly impossible to do by observing nonverbal behavior.

And although most people believe otherwise, the evidence is very clear—when it comes to detecting deception, people’s perceptions are no better than flipping a coin (see Science News).

Why is spotting a liar so difficult?

And what’s the best way to catch liar?

Reasons why detecting deception is hard to do.

  1. Watching for Nonverbal Cues Is Not Very Useful

    Despite popular belief, there are no consistent nonverbal cues associated with lying (see nonverbal cues).

    The nonverbal cues that have been identified vary widely from person to person, situation to situation, and according to the nature of the lie being told.

    And when nonverbal cues have been identified—even after looking at thousands of liars and truth-tellers—the findings cannot be applied to any given individual.


    To begin with, most signs of lying occur too quickly to be seen with the naked eye. If deception is revealed, it usually happens through micro expressions—brief flashes of one’s true emotional state (see facial expression test).

    More importantly, findings based on group averages cannot be applied to individuals.

    For instance, if you know that smokers have a shorter lifespan than nonsmokers—and you know that I don’t smoke—based on that information, can you tell when I’m going to die? Can you even tell me that I’m going to live longer than most smokers? What if I were to die tomorrow?

    And here lies the problem: statistics are great for describing groups, but you can’t use them to determine what any given individual is going to do. Statistics taken from groups can only be applied to groups, not specific individuals. So, even though smokers as a group will not live as long as non-smokers as a group, some smokers will live much longer than I will.

    A recent New York Times article on breast cancer does a much better job of making this point:

    "...cancer doctors dislike applying statistics derived from huge groups to individual patients. Some people do much better than average and some worse."

    The same holds true when it comes to detecting deception. If you see someone fidgeting while speaking, is that person lying? Who knows? Liars as a group may fidget more when lying, but any given individual may fidget a lot more or a lot less than other individuals in any given situation.

    The blog Truth, Lies and Romance, also provides a concrete example of the problems encountered when trying to use group averages to identify what specific individuals are likely to do.

    And to make matters even more complicated, the body language that people focus on the most—like breaking eye contact—simply has nothing to do with lying.

  2. Lying is Easy

    Detecting deception is also difficult because, despite what most people think, lying is very easy to do. Children learn to lie at an early age and they are very good at it (see lying comes easy).

    Our skills at lying only increases as we get older. In fact, adults lie every day without much awareness of what they are doing (see daily journals). Ironically, people lie so often that they actually begin to believe their own lies.

  3. Over-Confidence Provides Comfort, But It Hurts Accuracy

    Not only are people good at lying, but most people like to think that they can tell when a lie is being told.

    Believing that we are good at detecting deception provides a sense of security (it helps us feel that we are in control of our world). Holding such a belief, however, also makes it more difficult to detect deception.

    To excel at any task, you need to have an accurate understanding of your skill level. If you think you’re an excellent singer, but in reality you aren’t, it will be very difficult for you to make any improvements in your singing.

    And the same goes for detecting deception. Most people overestimate their skill level, and their overconfidence in their ability to spot a liar actually works against them when they seek to improve their detection skills (see detection confidence).

  4. Most People Try to Avoid the Truth

    Finally, detecting deception is difficult because most people don’t really want to know the truth. The truth often hurts and many people go to great lengths to avoid acknowledging it (see truth hurts).

    Because of our tendency for self deception, many people would rather believe a pleasant lie than deal with an unpleasant truth, especially when it comes to love and romance (see catching lovers lying).

At the end of the day, there is no fullproof way to detect deception by watching a person’s nonverbal behavior. Even professionals with years of training cannot tell when the truth is being told (see detection training).

Given these facts, it should come as no surprise that only about 2-4 people out of 1,000 can consistently detect deception; these people are called "truth wizards." You can meet a real truth wizard on her blog.

So, what is the best way to detect deception?

Unfortunately, the best way to detect deception is through some form of surveillance or careful observation:

And it also helps to create situations where other people are more likely to tell you the truth (see get others to be honest).

For a much more detailed look at the problems and pitfalls of trying to detect deception in a romantic relationship, please see our section on detecting deception.

Related Information:

See more common questions.

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